About a month ago, I was talking to a man that sells hardware and support to small businesses (almost exclusively non-technical ones at that) for a living. He said his company spends a surprising amount of time downgrading Vista machines to XP - the majority of Vista installs sold to business customers come back for downgrading.

Whether it's an unsatisfactory experience or unfamiliarity that's the cause, it's a losing proposition for Microsoft if that's a common pattern.